Basic Linux Commands

A shell is a command-line interpreter: it takes commands and executes them.Bash (Bourne-again shell) is the default shell for most current Linux distributions (and Mac OS X) and can be run on most Unix-like operating systems.To check what shell you are currently using, open the console, type echo $SHELL, and press Enter. It should return a pathname ending with /bash.

W - shows all users and what they are doing
finger - displays information about system users
who - show who is logged on
pwd - print working directory
history-shows previous used commands
uname - shows system information
ip addr - reports your IP address
ls - displays directory contents
ls -l - like ls,but in a more readable format
su - switch user/super user
nano - basic text editor
kwrite - gui text editor
free - display memory usage
df - displays free disk space(df -h - displays in more readable format)
man [command] - gives more information about command
ps - lists the current running processes on your Linux system
kill and killall commands - used to kill|terminate running processes

whoami - prints ur login name
last-Show listing of users last logged-in on your system.
history | more - Show the last (1000 or so) commands executed from the command line on the current account. The "| more" causes the display to stop after each screenful.
uptime - Show the amount of time since the last reboot.
top - Keep listing the currently running processes, sorted by cpu usage (top users first). In KDE, you can get GUI-based Ktop from "K"menu under "System"-"Task Manager" (or by executing "ktop" in an X-terminal).